1. Field of the Invention
The present invention relates to a semiconductor light-emitting device and a method for manufacturing the semiconductor light-emitting device.
2. Description of the Related Art
Semiconductor light-emitting devices such as light-emitting diodes (LEDs), for example, include a light-emitting portion 20 composed of a projecting laminated body obtained by laminating an n conductivity type first compound semiconductor layer 21, an active layer 23, and a p conductivity type second compound semiconductor layer 22 in sequence on a semiconductor light-emitting device manufacturing substrate (hereinafter may be simply referred to as a substrate 10). A first electrode (n-side electrode) 41 is disposed on the substrate 10 or an exposed portion 21a of the exposed first compound semiconductor layer 21. A second electrode (p-side electrode) 130 is disposed on the top face of the second compound semiconductor layer 22. Such semiconductor light-emitting devices can be classified into two types of devices such as a semiconductor light-emitting device in which light from the active layer 23 is emitted through the second compound semiconductor layer 22 and a semiconductor light-emitting device in which light from the active layer 23 is emitted through the first compound semiconductor layer 21 (called a bottom emission type for the sake of convenience).
In a bottom emission type semiconductor light-emitting device of the related art, normally, a reflecting electrode that reflects visible light from the active layer 23 is often used as the second electrode 130 as shown in FIG. 10 to maintain high light-emitting efficiency. The second electrode 130 as a reflecting electrode includes, for example, a lower layer 131 composed of silver (Ag) and an upper layer 132 composed of nickel (Ni) (e.g., refer to C. H. Chou, et al., “High thermally stable Ni/Ag(Al) alloy contacts on p-GaN”, Applied Physics Letters 90, 022102 (2007)). Herein, since the lower layer 131 is composed of silver (Ag), a high light reflectance can be achieved. In addition, since the upper layer 132 is composed of nickel (Ni), the degradation caused by oxidation of the lower layer 131 and the occurrence of migration are prevented. In the drawing, reference numeral 42 denotes an insulating layer and reference numerals 43A and 43B denote contact portions.
Normally, the upper layer 132 covers the lower layer 131. Herein, the distance from the edge of the lower layer 131 to the edge of the upper layer 132 is defined as D1. The region of the upper layer 132 from the edge of the lower layer 131 to the edge of the upper layer 132 is referred to as an upper layer protruding region for the sake of convenience. The distance from the edge of the upper layer 132 to the edge of the projecting laminated body is defined as D2. The region of the projecting laminated body from the edge of the upper layer 132 to the edge of the laminated body is referred to as a laminated body exposed region for the sake of convenience. The upper layer protruding region surrounds the lower layer 131 so as to form a frame. The laminated body exposed region surrounds the upper layer protruding region so as to form a frame.